Why People Leave Medicare Advantage Plans — and How to Switch Back

The top reasons people leave Medicare Advantage

Medicare Advantage (Part C) plans bundle hospital, medical, and usually drug coverage through a private insurer, often with low or $0 premiums and extra perks. The trade-off is that the plan manages your care through networks and prior authorization — and those trade-offs are what drive most people to leave.

Federal reviews have flagged that some prior-authorization denials involved care that actually met Medicare's own coverage rules, meaning patients were sometimes denied services they were entitled to. Frustration with denials and slow payment has also led a number of hospitals and health systems to stop contracting with certain Advantage plans for 2026, so some members lose access to a preferred doctor or hospital even if they keep their plan.

• Prior-authorization denials and delays for tests, procedures, or post-hospital care
• Networks shrinking as hospitals and physician groups drop specific plans
• Plan exits — some insurers stopped offering plans in certain counties for 2026, forcing members to find new coverage
• Benefit or drug-formulary changes that raise out-of-pocket costs year to year
• Surprise costs when traveling or needing out-of-network care

When you're actually allowed to switch

You can't drop a Medicare Advantage plan whenever you want. There are set windows, and missing them can lock you in for the rest of the year.

The Medicare Advantage Open Enrollment Period runs January 1 through March 31 and is only for people already in an Advantage plan. During it you can make one change: switch to a different Advantage plan, or return to Original Medicare (and add a standalone Part D drug plan). The change takes effect the first day of the following month.

The fall Annual Enrollment Period, October 15 through December 7, is broader — anyone can join, switch, or drop a plan, with coverage starting January 1. Outside these windows you generally need a Special Enrollment Period, which can apply if your plan leaves your area, you move out of the service area, or you qualify through other life events.

• Jan 1 – Mar 31: Medicare Advantage Open Enrollment — one change, for current MA members only
• Oct 15 – Dec 7: Annual Enrollment Period — open to everyone, coverage starts Jan 1
• Special Enrollment Periods: triggered by plan exits, moves, or other qualifying events

The Medigap catch most people miss

Returning to Original Medicare is the easy part. The hard part is what fills its gaps. Original Medicare has no annual out-of-pocket limit, so many people pair it with a Medicare Supplement (Medigap) policy — but Medigap is not guaranteed to anyone who wants it.

In most states, once your one-time Medigap open enrollment window has passed, insurers can use medical underwriting: they can review your health and charge more, or deny coverage, based on pre-existing conditions. That means someone who develops health problems while on an Advantage plan may not be able to buy the Medigap policy they'd want when switching back.

There are protections in limited cases. A 'trial right' lets you return to Medigap without underwriting if you're in your first 12 months of an Advantage plan that you joined when first eligible at 65, or if you dropped a Medigap policy to try Advantage for the first time. A handful of states also guarantee Medigap access without underwriting. Rules vary by state and situation, so confirm yours before you drop a plan.

What switching back to Original Medicare costs in 2026

Original Medicare has its own premiums, deductibles, and coinsurance. Knowing these helps you compare honestly against your Advantage plan's costs.

These are the standard 2026 federal amounts set by CMS. A separate Part D drug plan and any Medigap policy you add come with their own premiums on top.

• Part B: $202.90/month premium; $283 annual deductible; then you pay 20% coinsurance for most covered services
• Part A: premium-free with 40+ work quarters; $1,736 deductible per benefit period; days 61–90 cost $434/day; lifetime reserve days $868/day
• Part D drug coverage: $2,100 annual out-of-pocket cap; national base premium $38.99/month
• Higher earners pay IRMAA surcharges: Part B totals $284.10–$689.90/month and Part D adds $14.50–$91.00/month when 2024 income exceeded $109,000 (single) or $218,000 (joint)
• Late-enrollment penalties are permanent — Part B adds 10% per full 12 months you delayed; Part D adds 1% of $38.99 per uncovered month

How to leave your Medicare Advantage plan

If you've confirmed you're in a valid switching window and checked your Medigap options, the process itself is straightforward.

• Confirm your window (MA Open Enrollment, Annual Enrollment, or a Special Enrollment Period)
• Decide your destination: a different Advantage plan, or Original Medicare plus a standalone Part D plan
• If returning to Original Medicare, line up Part D and price a Medigap policy first — and check whether you'll face underwriting
• Enroll in the new coverage; in most cases joining a new plan or Part D plan automatically disenrolls you from the old Advantage plan
• Use the official Medicare Plan Finder at Medicare.gov or call 1-800-MEDICARE (1-800-633-4227) to verify and enroll
• Watch the effective date so you're never left with a coverage gap